CN1746775A - Lithographic apparatus and device manufacturing method - Google Patents

Abstract

A lithographic apparatus comprising: an illumination system for conditioning a radiation beam; a support supporting a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table supporting a substrate; a projection system for projecting the patterned radiation beam onto a target portion of the substrate; a liquid supply system for at least partially filling a gap between a final element of the projection system and the substrate with a liquid; a seal member substantially containing said liquid in said gap between said final element of the projection system and said substrate; and an element to control and/or compensate for evaporation of immersion liquid from the substrate.

Description

Lithographic apparatus and device manufacturing method

technical field

The invention relates to lithographic apparatus and methods for fabricating devices.

Background technique

A lithographic apparatus is a machine that applies a desired pattern to a substrate, usually a target portion of the substrate. A lithographic apparatus may be used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device, alternatively called a mask or reticle, may be used to create the circuit pattern to be formed on the individual layers of the IC. This pattern can be transferred to a target portion (eg, a portion comprising one or a few dies) on a substrate (eg, a silicon wafer). Transfer of the pattern is typically by imaging onto a layer of radiation sensitive material (resist) disposed on the substrate. Typically, a single substrate will contain successfully patterned circuitry adjacent to the target portion. Known lithographic apparatuses include so-called steppers, in which each target portion is irradiated by simultaneously exposing the entire pattern to the target portion, and so-called scanners, in which light is irradiated by exposing the entire pattern to the target portion simultaneously The radiation beam on the scan pattern is used to illuminate each target portion and simultaneously scan the substrate parallel or antiparallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern on the substrate.

It is proposed to immerse the substrate in a lithographic projection apparatus into a liquid with a relatively high refractive index, such as water, to fill the space between the last element of the projection system and the substrate. The purpose of this is to image smaller features since the exposure radiation has a shorter wavelength in the liquid. (The effect of the liquid can also be considered to increase the effective NA of the system and also increase the depth of focus.) Other immersion liquids have been proposed, including water with solid particles (eg quartz) suspended therein.

However, immersing the substrate or substrate and substrate table into a liquid container (see eg US4509852, the entire content of which is hereby incorporated by reference), means that there is a large amount of liquid that must be accelerated during scanning exposure. This requires additional or more powerful motors, and turbulence in the liquid can cause undesirable and unpredictable effects.

One of the proposed solutions is to use a liquid confinement system to provide liquid for the liquid supply system only on a localized area of the substrate and between the last element of the projection system and the substrate (the substrate usually has a greater thickness than the last element of the projection system). large surface area). One way that has been proposed for its arrangement is disclosed in WO99/49504, the entire content of which is hereby incorporated by reference. As described in Figures 2 and 3, the liquid is supplied onto the substrate through at least one inlet IN, preferably in the direction of movement of the substrate relative to the final element, and after having passed under the projection system, through at least one outlet OUT remove. That is, as the substrate is scanned under the element in the X direction, liquid is supplied at the +X side of the element and taken away at the -X side. Figure 2 schematically shows an arrangement where liquid is supplied through inlet IN and taken off on the other side of the element through outlet OUT, which is connected to a low pressure source. In the illustration of Figure 2, the liquid is supplied along the direction of movement of the substrate relative to the final element, although this need not be the case. Multiple orientations and numbers of inlets and outlets located around the final element are possible, an example is illustrated in Figure 3, providing four sets of inlets with outlets on either side in a regular pattern around the final element.

Another solution proposed is to provide the liquid supply system with sealing means extending along at least a part of the boundary of the space between the last element of the projection system and the substrate table. Such a solution is illustrated in Figures 4a and 4b. The packaging member is substantially fixed relative to the projection system in the XY plane, although there is some relative movement in the Z direction (in the direction of the optical axis). A seal is formed between the sealing member and the surface of the substrate. Preferably, the seal may be a contactless seal, such as a gas seal. Such a system with a gas seal is disclosed in European Patent Application No. 03252955.4, the entire content of which is hereby incorporated by reference.

Fig. 4b shows an example arrangement for the sealing member 12 arranged to contain an immersion liquid in a localized area 25 under the projection lens PL. The sealing member 12 has an extractor EX arranged to extract liquid from the localized area 25 through the strainer GZ. The Extractor EX can extract liquids and gases or just liquids. The recess RE is provided radially outside the extractor EX, and the gas seal 27 is provided radially outside the recess RE. The gas seal 27 forms a jet of gas JE for drying the surface of the substrate W and/or reducing the amount of liquid that seeps through the sealing member 12 .

The concept of a twin or dual stage immersion lithography apparatus is disclosed in European Patent Application No. 03257072.3. This apparatus has two stages for supporting the substrate. Sand entry leveling without immersion liquid at a first location with one table and exposure with a second location with immersion liquid present. Optionally, the device has only one station.

While providing an improved solution, it has been found that the introduction of the immersion liquid causes errors in the image produced on the substrate, including alignment errors between one layer and the next (i.e., overlay errors), defocus and deviation.

Contents of the invention

It would be desirable to provide a system that reduces lithography errors due to immersion liquids.

According to one aspect of the invention there is provided a lithographic apparatus comprising: an illumination system arranged to condition a radiation beam; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form patterned radiation beam; a substrate table configured to support a substrate; a projection system arranged to project a patterned beam of radiation onto a target portion of a substrate; arranged to at least partially fill between the projection system and the substrate with a liquid a liquid supply system in the gap; a sealing member arranged to substantially contain the liquid in the gap between the last element of the projection system and the substrate; and arranged to control the liquid supplied by the liquid supply system The liquid evaporation controller is the net rate of liquid evaporation.

According to another aspect of the present invention, there is provided a lithographic apparatus comprising: an illumination system arranged to condition a radiation beam; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned a substrate table configured to support a substrate; a projection system arranged to project a patterned radiation beam onto a target portion of a substrate; a final element of the projection system arranged to at least partially fill with a liquid and a liquid supply system for a gap between said substrates; a sealing member arranged to substantially contain said liquid in said gap between said final element of a projection system and said substrate; a substrate table scanning system, arranged to move the substrate table along a predetermined scan path relative to the sealing member, thereby scanning the target portion over the surface of the substrate; A substrate heater that heats at least a portion of the substrate by at least one of a scan path of the stage relative to the sealing member, a local substrate temperature, and a local substrate table temperature.

According to another aspect of the present invention, there is provided a lithographic apparatus comprising: an illumination system arranged to condition a radiation beam; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned a radiation beam; a substrate table configured to support a substrate; a projection system arranged to project a patterned radiation beam onto a target portion of a substrate; arranged to at least partially fill a final element of said projection system and all a liquid supply system for a gap between said substrates; a sealing member arranged to substantially contain said liquid in said gap between said final element of a projection system and said substrate; arranged to control the flow rate from said sealing A gas seal of the amount of liquid that escapes from a member through a gap defined on one side of the boundary of said sealing member and on a second side of said substrate, said gas seal comprising a gas outlet through which gas supply to the zone within the slit, and a vacuum exhaust inlet through which the gas supplied by the gas outlet is removed from the zone within the slit, the gas outlet and the vacuum exhaust inlet being respectively connected to the A gas outlet pipe and a vacuum exhaust inlet pipe in the sealing member, wherein the sealing member further includes a sealing member temperature stabilizer.

According to another aspect of the present invention, there is provided a lithographic apparatus comprising: an illumination system arranged to condition a radiation beam; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned a radiation beam; a substrate table configured to support a substrate; a projection system arranged to project a patterned radiation beam onto a target portion of a substrate; arranged to at least partially fill a final element of said projection system and all A liquid supply system for a gap between said substrates; a sealing member arranged to substantially contain said liquid in said gap between said final element of a projection system and said substrate; for controlling flow through A substrate table heat exchange liquid controller for the temperature and flow rate of the heat exchange liquid embedded in the channel network in the substrate table.

According to another aspect of the present invention, there is provided a lithographic apparatus comprising: an illumination system arranged to condition a radiation beam; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned a radiation beam; a substrate table configured to support a substrate; a projection system arranged to project a patterned radiation beam onto a target portion of a substrate, wherein the substrate table includes at least one integrated localized temperature control system, the The control system includes a temperature sensor coupled to a heater configured to generate heat when the local temperature measured by the temperature sensor is lower than a predetermined reference value, and when the local temperature rises to the predetermined reference value Stop generating heat when above.

According to another aspect of the present invention, there is provided a lithographic apparatus comprising: an illumination system arranged to condition a radiation beam; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned A radiation beam; a substrate table configured to support a substrate; a projection system arranged to project a patterned radiation beam onto a target portion of a substrate; arranged to measure the substrate, the substrate table, and the substrate holder at least one temperature sensor for the temperature of at least a portion of at least one of the projectors; and a projection system controller configured to adjust a property of the patterned radiation beam in response to the temperature measured by the at least one temperature sensor.

According to another aspect of the present invention, there is provided a lithographic apparatus comprising: an illumination system arranged to condition a radiation beam; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned a substrate table configured to support a substrate; a projection system arranged to project a patterned radiation beam onto a target portion of a substrate; a final element of the projection system arranged to at least partially fill with a liquid and a liquid supply system for a gap between said substrates; a sealing member arranged to substantially contain said liquid within said gap between said final element of a projection system and said substrate; a substrate table transfer system, arranged to move the substrate along a predetermined path relative to the sealing member, thereby moving the target portion on the surface of the substrate; and a microwave source and a microwave containment device, arranged together to Heat is supplied to the liquid on the substrate surface.

According to another aspect of the present invention, there is provided a method of manufacturing a device comprising: providing an illumination system arranged to condition a radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table configured to support a substrate; providing a projection system arranged to project the patterned radiation beam onto a target portion of the substrate; providing an arrangement to at least partially fill the substrate with a liquid A liquid supply system for a gap between the last element of the projection system and the substrate; providing a sealing member arranged to substantially contain the liquid in the gap between the last element of the projection system and the substrate and controlling the net rate of evaporation of liquid provided by said liquid supply system.

According to another aspect of the present invention, there is provided a method of manufacturing a device comprising: providing an illumination system arranged to condition a radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table configured to support a substrate; providing a projection system arranged to project the patterned radiation beam onto a target portion of the substrate; providing an arrangement to at least partially fill the substrate with a liquid A liquid supply system for a gap between the last element of the projection system and the substrate; providing a sealing member arranged to substantially contain the liquid in the gap between the last element of the projection system and the substrate providing a substrate table displacement system arranged to move the substrate table along a predetermined scan path relative to the sealing member, thereby moving the target portion on the surface of the substrate; and according to position, speed , acceleration, and at least one of a predetermined path of the substrate table relative to the sealing member, a local substrate temperature, and a local substrate table temperature to heat a portion of the substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a device comprising: providing an illumination system arranged to condition a radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table configured to support a substrate; providing a projection system arranged to project the patterned radiation beam onto a target portion of the substrate; providing an arrangement to at least partially fill the substrate with a liquid A liquid supply system for a gap between the last element of the projection system and the substrate; providing a sealing member arranged to substantially contain the liquid in the gap between the last element of the projection system and the substrate providing a gas seal arranged to control the amount of liquid escaping from the sealing member through a gap defined on one side of the boundary of the sealing member and on the second side of the substrate, providing a gas seal , which includes a gas inlet through which gas is supplied to a region within said slit, and a vacuum exhaust outlet through which gas supplied by said gas inlet is removed from a region within said slit, said gas inlet and said The vacuum exhaust outlets are respectively connected to the gas inlet pipe and the vacuum exhaust outlet pipe embedded in the sealing member, and stabilize the temperature of the sealing member.

According to another aspect of the present invention, there is provided a method of manufacturing a lithographic device, comprising: providing an illumination system arranged to adjust a radiation beam; providing a support for supporting a patterning device capable of imparting a pattern on its cross-section Radiating a beam to form a patterned radiation beam; providing a substrate table configured to support a substrate; providing a projection system arranged to project a patterned radiation beam onto a target portion of a substrate; providing an arrangement to at least partially utilize a liquid A liquid supply system that fills a gap between the last element of the projection system and the substrate; providing an arrangement to substantially contain the liquid in the gap between the last element of the projection system and the substrate A sealing member; providing a channel network embedded in the substrate table, and controlling the temperature and the flow rate of the heat exchange liquid arranged to flow through the associated channel network.

According to another aspect of the present invention, there is provided a method of manufacturing a device comprising: providing an illumination system arranged to condition a radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table configured to support a substrate; providing a projection system configured to project a patterned radiation beam onto a target portion of a substrate; wherein the substrate table includes at least one integrated A local temperature control system for a local temperature control system comprising: a temperature sensor coupled to a heater arranged to generate heat when the local temperature as measured by the temperature sensor falls below a predetermined reference value, and when Heat generation ceases when said local temperature rises above said predetermined reference value.

According to another aspect of the present invention, there is provided a method of manufacturing a device, comprising: providing an illumination system arranged to adjust a radiation beam; providing a support for supporting a patterning device capable of imparting a pattern on its cross-section to the radiation beam to form a patterned radiation beam; provide a substrate table configured to support a substrate; provide a projection system configured to project a patterned radiation beam onto a target portion of a substrate; provide at least one temperature sensor, the temperature sensor measuring a temperature of at least a portion of at least one of the substrate, the substrate table, and a substrate holder; and adjusting a property of the patterned radiation beam in response to the temperature measured by the at least one temperature sensor.

According to another aspect of the present invention, there is provided a method of manufacturing a device comprising: providing an illumination system arranged to condition a radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table configured to support a substrate; providing a projection system arranged to project the patterned radiation beam onto a target portion of the substrate; providing an arrangement to at least partially fill the substrate with a liquid A liquid supply system for a gap between the last element of the projection system and the substrate; providing a sealing member arranged to substantially contain the liquid in the gap between the last element of the projection system and the substrate providing a substrate table transfer system configured to move the substrate along a predetermined path relative to the sealing member, thereby moving the target portion on the surface of the substrate; and using a microwave source and a microwave container The device provides heat to a liquid on the surface of the substrate.

Description of drawings

Embodiments of the present invention will be described below by way of example only with reference to the accompanying schematic diagrams, in which corresponding reference characters represent corresponding parts, wherein:

Figure 1 depicts a lithographic apparatus according to an embodiment of the invention;

Figures 2 and 3 describe a liquid supply system used in a prior art lithographic projection apparatus;

Figures 4a and 4b describe a liquid supply system of a lithographic projection apparatus according to another prior art;

Figure 5 depicts a sealing member showing the interaction with a pressurized gas humidity controller, an immersion liquid temperature controller and a pressurized gas temperature controller in accordance with an embodiment of the present invention;

FIG. 6 depicts a sealing member, a gas shower outlet and a gas shower outlet controller according to an embodiment of the present invention;

Figure 7 depicts a top view of a substrate table of a system including a localized heater and a substrate temperature controller according to an embodiment of the present invention;

Figure 8 depicts a side view of the substrate table of Figure 7, also showing a plurality of temperature sensors, a substrate table path-defining device and a substrate heater within the sealing member;

Figure 9 depicts a top view of a substrate table showing the geometry of the substrate heater to dissipate more energy in the lower region of the substrate table than in the upper region;

Figure 10 depicts an array of independently controllable substrate heaters according to an embodiment of the invention;

Figure 11 depicts a side view of the structure of Figure 10, also showing the interaction of the heater array controller and predetermined algorithm input means;

12 depicts a partial view of a seal member showing thermal isolation sleeves and seal member heaters for the vacuum exhaust inlet and vacuum exhaust line, in accordance with an embodiment of the present invention;

Figure 13 depicts the interaction between a seal member and a seal member temperature stabilizer in accordance with an embodiment of the present invention;

Figure 14 depicts a sealing member comprising a network of liquid transport channels and a liquid supply system according to an embodiment of the invention;

Figure 15 depicts a sealing member and substrate table comprising a network of liquid transport channels and an array of independently controllable heaters controlled by a substrate temperature controller including a substrate table heat exchange liquid controller and substrate heater controller;

Figure 16 depicts a substrate table with a channel network and recirculation channels according to an embodiment of the invention;

Figures 17 and 18 depict a substrate table according to Figure 16 with a recirculation groove, sealed by a sealing ring according to an embodiment of the invention;

Figure 19 depicts a lithographic apparatus showing the location of temperature sensors in the substrate table and in the sealing member according to an embodiment of the invention;

Figure 20 depicts an enlarged view of a substrate table in a substrate region showing a microscopic temperature control system setup in accordance with an embodiment of the present invention;

Figure 21 depicts a projection system controller and thermally induced deformation calculator in accordance with an embodiment of the present invention;

Figure 22 depicts a microwave source and microwave containment cage for heating the immersion liquid on the surface of the substrate;

Figure 23 depicts the setup of the resistive heating strip and associated current;

Figure 24 depicts a single resistive strip used as a local temperature sensor for a local heater system;

Figure 25 depicts the setup for induction heating of the substrate table WT;

Figure 26 depicts an apparatus for generating airflow with controlled humidity levels;

Figure 27 depicts a heat exchanger for controlling the temperature of the gas stream;

Figure 28 depicts a ventilation system for enabling stable operation of the humidifier cartridge;

Detailed ways

Fig. 1 briefly describes a lithographic apparatus according to an embodiment of the present invention. The equipment includes:

An illumination system (illumination device) IL is arranged to condition the radiation beam B (eg UV radiation or DUV radiation).

A support structure (eg mask table) MT is provided to support the patterning device (eg mask) MA and is connected to a first positioner PM for precisely positioning the patterning device according to specific parameters.

a substrate table (e.g. wafer table) WT arranged to support a substrate (e.g. a resist-coated wafer) W and connected to a second positioner PW for precisely positioning the substrate according to specified parameters; and

A projection system (eg a refractive projection lens system) PS is arranged to project the pattern imparted to the radiation beam B by the patterning device MA onto a target portion C of the substrate W (eg comprising one or more dies).

An illumination system may include a variety of optical elements, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical elements, or any combination thereof, for directing, shaping, or controlling radiation.

The support structure supports the patterning device, that is, bears the weight of the patterning device. It supports the patterned device in a manner that depends on the orientation of the patterned device, the design of the lithographic apparatus, and other conditions, such as whether the patterned device is held in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure may be a frame or a table, for example, which may be fixed or movable as desired. The support structure may ensure that the patterning device is in a desired position, for example with respect to the projection system. Any use of the terms "reticle" or "mask" herein may be considered synonymous with the more general term "patterning device".

The term "patterning device" as used herein should be interpreted broadly to refer to any device that can be used to impart a pattern in its cross-section to a radiation beam, for example to create a pattern in a target area of a substrate. It should be noted that the pattern imparted to the radiation beam may not exactly correspond to the pattern in the target area of the substrate, eg if the pattern comprises phase shifting properties or so-called assist properties. Typically, the pattern imparted to the radiation beam will correspond to a specific functional layer in a device produced in the target portion, such as an integrated circuit.

Patterning devices can be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include mask types such as binary, alternating phase-shift and attenuated phase-shift, and various hybrid masks. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted to reflect an incident radiation beam in different directions. The tilted mirrors impart a pattern in the radiation beam reflected by the array of mirrors.

The term "projection system" as used herein should be broadly interpreted to encompass any type of projection system including refraction, reflection, Catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof. Any use of the term "projection lens" herein may be considered synonymous with the more general term "projection system".

As described herein, the device is transmissive (eg, using a transmissive mask). Alternatively, the device may be reflective (eg using a programmable mirror array as described above, or using a reflective mask).

The lithographic apparatus may be of the type with two (dual stage) or multiple substrate stages (and/or two or more mask stages). In such "multi-stage" machines, when one or more other tables are used for exposure, additional tables may be used in parallel, or preparatory steps may be performed on one or more tables. The substrate W may be held directly by a substrate table WT (sometimes called a mirror block) and by a substrate holder (sometimes called a paddle or chuck), which in turn is held by the substrate table WT.

Referring to Fig. 1, an illumination device IL receives a radiation beam from a radiation source SO. For example when the source is an excimer laser, the source and lithographic apparatus may be separate mechanisms. In this case, the source is not considered to form part of the lithographic apparatus and the radiation beam is delivered from the source SO to the illumination device IL by means of a beam-splitting system BD comprising, for example, suitable steering mirrors and/or beam extender. In other cases the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The source SO and the illumination device IL, and if necessary the beam splitting system BD, together may be referred to as a radiation system.

The illumination device IL may comprise an adjuster AD for adjusting the angular intensity distribution of the radiation beam. In general, at least the outer and/or inner radiation range (often referred to as [beta]-outer and [beta]-inner, respectively) of the intensity distribution in the light aperture plane emitted by the lighting device can be adjusted. In addition, the illumination device IL may contain various other elements, such as an integrator IN and a concentrator CO. The illumination device can be used to condition the radiation beam to have a desired uniformity and intensity distribution across its cross-section.

The radiation beam B is incident on a patterning device (eg mask MA), which is fixed on a support structure (eg mask table MT) and is patterned by the patterning device. After passing through the mask MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam onto a target portion C of the substrate W. Using a second positioner PW and a positioning sensor IF (eg an interferometric device, a linear encoder or a capacitive sensor), the substrate table WT can be moved precisely, eg to position different target portions C in the path of the radiation beam B. Similarly, a first positioner PM and a further position sensor (which is not explicitly depicted in FIG. 1 ) can be used to precisely position mask MA for radiation, for example after mechanical repair from a mask library, or during scanning. Path positioning of bundle B. Typically, the movement of the mask table MT can be achieved using a long stroke assembly (coarse positioning) and a short stroke assembly (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate table WT may be achieved using a long-stroke assembly and a short-stroke assembly, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the mask table MT may only be connected to a short-stroke actuator, or may be fixed. Mask MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks described occupy dedicated target portions, they may be located in the gaps between target portions (here known as scribe-lane alignment marks). Similarly, where more than one die is provided on the mask MA, mask alignment marks may be located between the dies.

The device can be used in at least one of the following modes:

1. In step mode, mask table MT and substrate table WT remain substantially stationary, while the entire pattern imparted to the radiation beam is simultaneously projected onto target portion C at one time (ie a single static exposure). The substrate table WT is then shifted to the X and/or Y direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure area limits the size of the target portion C imaged in a single static exposure.

2. In scan mode, the mask table MT and the substrate table WT are scanned simultaneously while the pattern imparted to the radiation beam is projected onto the target portion C (ie single dynamic exposure). The velocity and direction of the substrate table WT relative to the mask table MT may be determined by the zoom-in (zoom-out) and reverse imaging properties of the projection system PS. In scanning mode, the maximum size of the exposure area limits the width (in the non-scanning direction) of the target portion in a single dynamic exposure, whereas the length of the scanning movement determines the height (in the scanning direction) of the target portion.

3. In other modes, while the pattern imparted to the radiation beam is projected onto the target portion C, the mask table MT supporting the programmable patterning device remains substantially stationary and the substrate table WT is moved or scanned. In this mode, a pulsed radiation source is typically employed and the programmable patterning device can be modified as required after each movement of the substrate table WT or between successive radiation pulses during scanning. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning devices, such as the programmable mirror arrays described above.

Combinations and/or variations of utilizing the modes described above, or utilizing entirely different modes may also be used.

According to one aspect of the present invention, overlay errors and other problems related to the presence of immersion liquid and sealing member 12 are addressed by a liquid evaporation controller that targets and controls the evaporation rate of immersion liquid in the region of the substrate. To evaporate, the liquid molecules absorb energy from the surroundings, especially if pumped away, and the resulting refrigeration can cause significant and non-uniform changes in the temperature of critical components such as the substrate W. Thermally induced deformations can lead to errors in the image that is finally written to the substrate. For example, evaporation of the immersion liquid remaining on the substrate after the passage of the sealing member 12 can result in a local temperature drop to 3K. As a result of this, typically single mechanical overlay errors in excess of 20nm can arise.

Figure 5 illustrates an arrangement of sealing member 12 according to one or more embodiments of the invention. The immersion liquid is contained in an immersion vessel 25 located between the last element of the projection system PL and the substrate W. The immersion liquid is contained within the immersion vessel 25 through the body of the sealing member 12 and a gas seal 27 on its lower periphery, which limits the amount of immersion liquid escaping from the immersion vessel 25 through the gap 22 . The gas seal 27 is connected to a pressurized gas supply system 30 which supplies pressurized gas to the gas seal 27 via the pressurized gas outlet 18 and the pressurized gas supply pipe 15 . The gas is sucked away through the vacuum exhaust inlet 17 and the vacuum exhaust pipe 14. Evaporating immersion liquid in the region of the gas seal 27 can be drawn off via the vacuum evacuation inlet 17 . Alternatively, liquid escaping the gas seal 27 may either enter the area under the sealing member 12 in the gap 22 or beyond the outer edge of the sealing member 12 to evaporate into the environment outside the substrate W outside the sealing member 12 .

Substances exist in both liquid and gaseous forms, and generally the situation is a dynamic equilibrium that exists when the rate of evaporation of the liquid and the rate of condensation of the vapor are balanced. The amount of cooling produced by evaporation is thus offset by the heat produced by condensation (where high energy gas molecules generate heat to their surrounding environment as part transitions to a low energy liquid state). The cooling energy thus depends on the net rate of evaporation (ie the difference between the number of molecules passing from liquid to gas state per unit time and the number of molecules passing from gas to liquid state per unit time). Both condensation and evaporation are statistical effects, and increasing the number of molecules involved will increase the rate of either process. Therefore, increasing the vapor concentration will increase the condensation rate and result in a decrease in the net rate of evaporation. Vapor is composed of water molecules, and the concentration can be directly related to relative humidity, defined as the amount of water vapor present in the percentage of the maximum amount present at a given temperature.

This understanding is exploited in accordance with embodiments of the present invention to control the cooling produced by the evaporation of the immersion liquid. As shown in Figure 5, a pressurized gas humidity controller 50, which is provided to interact with the pressurized gas supply system 30, provides pressurized gas to the gas seal 27, the relative humidity of which is controlled to be greater than 10%. Increasing the relative humidity of the gas increases the rate of condensation and thereby reduces the net rate of evaporation and the resulting cooling. Preferably the relative humidity is set within a predetermined range determined by reference calibration measurements. For controlled cooling purposes, the higher the relative humidity, the better. However, for very high relative humidity, the sealing member 12 may retain excess water in its wake. Also, if an insufficient mechanism is provided for the extraction of moist gas near the outer diameter of the sealing member, moisture may remain and interfere with the operation of the positioning sensor IF. Typically, therefore, the upper limit will depend on details of seal member construction and/or arrangement. Additionally or alternatively, the predetermined range may be greater than 40%. High relative humidity such as these can be achieved by using a lower working pressure than might otherwise be chosen for the sole purpose of obtaining optimum sealing performance (typically 6 bar may be used). Ideally, the operating pressure should be chosen to be as close to atmospheric pressure as possible while still providing sufficient flow rate for the gas bearing 27 to perform its function. The lower the operating pressure, the lower the relative humidity decreases as the pressurized gas expands upon exiting the pressurized gas supply system 30 .

The pressurized gas humidity controller 50 may be configured to respond to changes in the temperature of the substrate W and/or substrate table WT. These temperature changes may be determined via one or more temperature sensors 60 provided, for example, in the substrate table WT. According to an embodiment of the invention, the pressurized gas humidity controller 50 is arranged to compare the temperature of the substrate W and/or the substrate table WT and/or the substrate holder measured by the temperature sensor 60 at one or more points with a target temperature or temperature Tt. That is, where a single temperature sensor 60 is present, the pressurized gas temperature controller 50 compares this one temperature reading to a single target temperature Tt. When multiple temperature sensors 60 are present, the pressurized gas temperature controller 50 compares the multiple readings to a single target temperature Tt, or to multiple target temperatures Tt corresponding to, for example, particular regions of the substrate W. , and/or the corresponding region of the substrate table/substrate holder, thus corresponding to a special set of temperature sensor readings (for which averaged readings may be used internally). To reduce the difference between the measured and target temperatures, the pressurized gas humidity controller 50 now adjusts the relative humidity of the pressurized gas, the effect of which is controlled by a feedback controller such as a PID system.

Regulating the humidity of the gas supplied to the gas seal 27 is most effective for cooling caused by evaporation in the area of the gas seal 27 , especially around the vacuum exhaust inlet 18 and the vacuum exhaust pipe 14 . It is preferred to have additional mechanical means to control the net evaporation of liquid beyond the gas seal 27 and the exterior of the sealing member 12 . Such an arrangement according to an embodiment of the invention is illustrated in FIG. 6 . Here, a gas shower outlet 70 capable of providing a gas flow having a relative humidity controlled to be greater than 10% is provided. A gas shower humidity controller 75 is provided which is capable of either measuring, calculating or measuring the temperature at one or more points on the substrate W and/or substrate table/substrate holder based on calibration. Relative humidity is adjusted, as provided by one or more temperature sensors 60, and compared to a target temperature or temperature Tt. The preferred relative humidity range in this case is 40 to 50%. In this case a gas shower humidity controller 75 is provided in response to the temperature measurement which adjusts the relative humidity of the gas in order to reduce the difference between the measured and target temperature Tt. That is, where a single temperature sensor 60 is present, the gas shower humidity controller 75 compares this one temperature reading to a single target temperature Tt. When multiple temperature sensors 60 are present, the gas shower humidity controller 75 compares the multiple readings to a single target temperature Tt, or to multiple target temperatures Tt corresponding to, for example, particular regions of the substrate W. , and/or the corresponding region of the substrate table/substrate holder, thus corresponding to a special set of temperature sensor readings (for which averaged readings may be used internally). A feedback controller such as a PID system can control the efficiency of the process.

A gas shower humidity controller 75 may be provided to interact with the pressurized gas humidity controller 50 to ensure that the relative humidity of the gas provided by the gas seal 27 matches that of the gas shower outlet 70 . This feature provides a mechanism by which changes in relative humidity outside the gas seal 27 can be controlled and avoid interference with systems such as interferometers used to measure the position of the substrate table WT that might otherwise occur.

The substrate table WT is normally arranged to be moved relative to the projection system PL and sealing member 12 by the substrate table shifting system 100 (see FIG. 8 ) so that successive target areas of the substrate W can be exposed by the patterned radiation beam. This process can facilitate the small amount of impregnation liquid leaving the confinement of the impregnation vessel 25 despite the operation of the gas seal 27 . Embodiments arranged to reduce cooling of the element by reducing evaporation of the immersion liquid have been discussed above. According to an optional aspect of the present invention, errors caused by the cooling effect of the evaporating immersion liquid can be addressed by providing a substrate heater that depends on the position, velocity, acceleration and predetermined path of the substrate table WT relative to the sealing member 12 , and at least one of a local substrate W and/or substrate table WT temperature to heat at least a portion of the substrate W. The substrate heater can be heated by a number of mechanisms. These may include one or more of the following: infrared radiation sources, hot filament resistance heaters and hot gas jets. Important factors when determining which type of heater to use include how precisely and quickly the heat generation needs to be adjusted, and how efficiently the micro-shaped heater can be produced. Depending on whether the heater is to be embedded in or near the material (such as a hot filament, e.g., embedded in the substrate table WT), where the temperature of the material tends to be adjusted, or whether the heater operates at a distance (e.g., infrared radiation source or temperature-controlled gas injection source), the latter factor will be more or less important. In the case of a radiation source, the wavelength distribution of the radiation is chosen to be non-reactive with the resist composition on the substrate W (infrared radiation should be safe for most resists of interest). The choice of radiation intensity depends on the optical properties of the resist (eg its reflectivity). This can be determined by calibration measurements during the setup sequence of the lithographic apparatus. Calibration can also be performed in the production sequence as an additional measurement stage for each substrate where there may be process stage dependencies (eg due to changes in reflectivity). As described below, several embodiments of the present invention operate with the rule that at least one of the existing substrate heaters is activated during the substrate exposure procedure, i.e., when the sealing member 12 passes over the substrate W. Subset. However, systems that heat the substrate W prior to exposure in order to compensate for the unavoidable but expected cooling are also within the scope of the invention.

Figures 7 and 8 illustrate arrangements according to embodiments of the present invention that include embedding in the substrate table as a "local heater" 85, or in the sealing member 12 as a "remote heater" 86, or both. The heater 85/86 system. Each localized heater 85 is configured to primarily heat a particular region of the substrate W and may be used together to control the temperature profile of at least a portion of the substrate W. The remote heater 86 will heat different portions of the substrate W depending on the position of the sealing member 12 relative to the substrate W.

According to the first mode of operation including localized heaters 85, the heat output and relative timing of each heater may be adjusted to establish a starting temperature profile for the substrate W within a known time before the substrate exposure cycle begins. With reference to calibration measurements and/or test pattern analysis produced by the lithographic apparatus, the starting temperature profile can be selected to substantially compensate for cooling due to evaporation of the immersion liquid during the exposure cycle.

According to a second mode of operation comprising localized heaters 85, each of these heaters 85 may be set to switch to a heat emitting state, only when passing the sealing member 12 on the zone of positioning heating. For example, where the sealing member 12 (and thus the target area) moves relative to the substrate W along the path 150 between the initial die (or target area) 160 to the final die 170 as shown in FIG. 7 , The localized heater 85 can also be switched in a progressive manner substantially along the same path 150 . This can be achieved by programming the substrate temperature controller 110 to provide a series of time delayed activation signals that for each local heater 85 closely lag the predetermined path of the sealing member 12 relative to the substrate table WT. The predetermined path may be stored in the substrate table path determining means 90 . As an alternative or in addition, the activation sequence of the local heaters 85 can be derived from a further function of the substrate table path determining means 90 . For example the substrate table path determination means 90 may comprise means for measuring the position, velocity and/or acceleration of the substrate table WT and for feeding this information to the substrate temperature controller 110 (e.g. on the basis of interferometric measurements), The device can calculate at this point when each local heater 85 is activated. For example, the path determining means 90 may be arranged to transmit an activation signal to a given heater when it is identified that the sealing member 12 has moved away from or past a particular heater. The power provided by each local heater 85 can be set to be constant or vary over time, and be the same or different from other local heaters 85 . The optimal setting for each heater is to best compensate for energy losses due to evaporation in the area concerned. With a constant rate of liquid loss from the sealing member 12, substantially the same amount of energy is supplied by each heater 85 once activated (since once the sealing member 12 has passed, it can be found that the amount of liquid remaining on the substrate W is about to evaporate roughly constant). Alternatively, it may be found that more heat is needed in certain regions, such as when the sealing member 12 changes orientation relative to the substrate table WT. Calibration measurements can be made as a function of the path and velocity required for a particular substrate table to determine the most energy efficient way to operate the heater.

As shown in FIG. 8 , a remote heater 86 in the sealing member 12 may preferably be positioned around the periphery of the sealing member 12 . This setting allows the heater to be operated adjacent to the area where the evaporation process can extract the most heat. The layout was chosen to be set near the outer diameter as a compromise to avoid the area immediately around the gas seal 27 which is already actually occupied by holes, tubes and dust. Because they operate at a distance from the substrate W, heating mechanisms such as those based on radiation or hot gas jets would be more suitable. Generating a thermal surface on the basis of the sealing member 12 is one method by which a radiation source can be implemented. Thermal isolation of such devices from the remainder of sealing member 12 will improve the performance of this feature. Alternatively or additionally, infrared bulbs may be used.

As provided for the local heater 85 described above, the power of the remote heater 86 can be controlled depending on the direction of movement of the substrate table. For example, it may be arranged to provide more heat from one side of the sealing member 12 than the other. In one aspect of cooling, involving evaporating liquid escaping from the seal member 12, a remote heater 86 may be positioned on the trailing edge of the seal member 86 (where the immersion liquid may escape) at a firing ratio located at the seal member 12 ( Those remote heaters on the front edge of the substrate (W (here still dry) are higher heat. The efficiency of the remote heater 86 can be varied as desired by varying the energy and/or width of the heater 86 around the circumference of the seal member 12 . This latter parameter can be varied, for example, by sequentially activating different segments of the segmented heater 86 , or one heater 86 of the plurality of heaters 86 .

Although shown embedded in the substrate table WT or sealing member 12, it is understood that the heaters 85/86 may be located anywhere where they can affect the temperature of the substrate W. For example, the radiation emitting heater may be positioned in a separate body than the substrate table WT and sealing member 12 . When heating the substrate W prior to exposure, this can occur in an area remote from the area used for exposure to more easily implement the remote heater 86 .

The lithographic apparatus may also include a local temperature sensor 60 which is embedded in the substrate table WT in the example illustrated in FIG. 8 . According to an embodiment of the invention, these temperature sensors 60 are arranged to measure the temperature of each region of the substrate W and/or the corresponding region of the substrate table/substrate holder affected by each localized heater 85 . The information is input to substrate temperature controller 110, which can then calculate how to control the output of local heater 85 and/or remote heater 86 to reduce the difference between the target temperature Tt and the temperature measured by local temperature sensor 60 . Preferably, in this embodiment, heaters 85 and/or 86 may be provided to have a variable output other than a fixed output. In any case, a feedback controller (such as a PID) can be used to optimize the efficiency of the convergence process.

Modulating the temperature of the liquid supplied by the liquid supply system 130 may also control the temperature of the substrate W and/or the substrate table/substrate holder. For example, the impregnation liquid may be heated to a controlled temperature of greater than 295K. Figure 5 shows an embodiment of the invention including an immersion liquid temperature controller 120 arranged to cooperate with a liquid supply system 130 to perform this function. Control of the temperature of the immersion liquid may be achieved based on calibrated measurements or on readings from one or more temperature sensors 60 in order to select an immersion liquid temperature effective to compensate for evaporation heat losses. In the latter case, the output of the immersion liquid temperature controller 120 may be controlled to minimize the difference between the target temperature Tt and the temperature provided by the temperature sensor 60, the convergence process being controlled by a feedback controller such as a PID controller . That is, where a single temperature sensor 60 is present, the immersion liquid temperature controller 120 compares this one temperature reading to a single target temperature Tt. When a plurality of temperature sensors 60 are present, the immersion liquid temperature controller 120 compares the plurality of readings to a single target temperature Tt, or to a plurality of target temperatures Tt, e.g. corresponding to particular regions of the substrate W, and/or the corresponding area of the substrate table/substrate holder, thereby corresponding to a particular set of temperature sensor readings (for which averaged readings may be used internally).

Adjusting the temperature of the gas supplied by the pressurized gas supply system 30 may also control the temperature of the substrate W and/or the substrate table/substrate holder. For example, the pressurized gas may be heated to a controlled temperature greater than 300K. Since gas has a lower specific heat than liquid, the lower temperature limit here is higher than that required for the immersion liquid temperature controller 120 described above. According to one embodiment of the invention, the pressurized gas is provided at a temperature in the range of 300 to 320K. FIG. 5 shows an embodiment of the invention including a pressurized gas temperature controller 140 arranged to perform temperature control functions in conjunction with the pressurized gas supply system 30 . Temperature control of the pressurized gas may be achieved based on calibrated measurements or based on readings from one or more temperature sensors 60 . In the latter case, the output of the pressurized gas temperature controller 140 may be controlled to minimize the difference between the target temperature Tt and the temperature provided by the temperature sensor 60, the convergence process being controlled by a feedback controller, such as a PID controller . That is, where a single temperature sensor 60 is present, the pressurized gas controller 140 compares this one temperature reading to a single target temperature Tt. When multiple temperature sensors 60 are present, the pressurized gas controller 140 compares the multiple readings to a single target temperature Tt, or to multiple target temperatures Tt, e.g. corresponding to particular regions of the substrate W, and/or the corresponding region of the substrate table/substrate holder, and thus corresponds to a particular set of temperature sensor readings (for which averaged readings may be used internally).

As discussed above, the substrate heating requirement has a position dependence that is determined at least in part by the path of the sealing member 12 over the substrate W. As shown in FIG. At least two processes are believed to contribute to the cooling process: the evaporation of liquid in the gap 22 between the substrate W and the sealing member 12, and the residue left on the substrate W after exposure if the exposed area is wet. Evaporation of liquid. The cooling energy of the sealing member 12 (ie cooling from the first process) is constant in time, although it depends on the velocity of the sealing member 12 relative to the substrate W, among other factors. The cooling energy of the second process depends on the amount of liquid left on the substrate W, among other factors. The amount of cooling that needs to be compensated is generally a complex function of the two processes, resulting in a cooling energy with compound position dependence. Thermal conductivity in the substrate W is also an important factor, since cooling in the exposed parts of the substrate W means that unexposed areas of the substrate W will start to cool even before the sealing member 12 reaches them. One process at a time, however, can be estimated. For example, considering only direct cooling from the evaporation of residual immersion liquid on the substrate W, set the exposure of the substrate to about 30 seconds, the time between the final exposure and the unloading of the substrate of about 5 seconds, and as in Fig. 7 The indicated exposure sequence 150 expects approximately 20% to 30% more heat to be extracted by this mechanism at the first exposed location 160 than at the last exposed location 170 . In the particular embodiment described above, including the substrate heaters 85/86, this effect is taken into account by delaying the activation of the individual heaters along the path of the sealing member 12. A similar effect can also be provided by arranging the substrate heater to provide lower radiation at the target area on the substrate W where the projection system is arranged to project the patterned radiation beam at the first time and progressively at the target area on the substrate W. This is achieved by providing higher heat from the heat in which the projection system PL is arranged to project the patterned radiation beam at a later time. This setting can be varied to give more complex site dependent heating depending on the cooling characteristics of the particular setup to be compensated.

While it is technically possible to locate multiple localized heaters 85 at many different locations on the substrate W, it is practical, efficient, and significantly less expensive to provide a more limited number of heaters and place them substantially along the sealed Component 12 path settings. This type of setup is depicted in Figure 7. Here, an elongated substrate heater 85, such as a heating filament, is arranged so that an independently controllable element is connected to the main scanning or binning axes 181-187 (each corresponding to a row of dies) of the sealing member 12 on the substrate W. ) one of the alignment. In the example shown, each hot filament 85 is arranged to emit a constant amount of heat per unit length, and is arranged so that the hot filament aligned with the main scan or step axis 187 has the greatest heat generation, which is aligned with 186 The next highest heat generation, etc., which progressively decreases until reaching the final hot filament corresponding to the main scanning or stepping axis 181, which distributes the lowest heat generation.

Wherein a large number of localized heaters are provided at different locations (eg between each substrate 100 and 700), preferably localized heaters as close as possible to the surface of the substrate W. Whereas in the setup shown in FIGS. 7 and 8 , few heaters are provided, and it is preferable to locate the heaters substantially farther so that each heater will have effective control over a greater portion of the substrate W. .

Figure 9 shows an arrangement in which a continuous thermal filament heater 85 is provided to heat the substrate W. In the example shown, the hot filament heater 85 is arranged to follow to some extent the path of the seal member 12 which has a main scan axis 181-187 substantially parallel to the seal member 12 (as shown in FIG. The longer portion 195 in the scanning direction). However, the pitches 191-193 provided between these longer features become shorter and shorter towards the bottom end of the substrate W, as shown, which corresponds to the region where the substrate W will be exposed first. (ie pitch 191 > pitch 192 > pitch 193). This means that the hot filament heater 85 can give the simplest and most robust construction (where the heat generation per unit length is constant and can actually correspond to elongated resistive elements of equal cross-section) and still provide a lining facing therein. The region of the substrate W that will be exposed first becomes larger, which is the region of the substrate W that requires the greatest correction for the cooling effect. Alternatively and/or additionally, hot filament heater 85 may be arranged to provide a heating value per unit length that varies along its length (e.g., increasing in the direction shown towards the bottom end of substrate W). . In the case of a hot filament that operates by dissipation of electricity related to the current passing through its length, the variable can be obtained by changing the cross-section (for example, to provide a thinner hot filament that becomes more energy-demanding) or by changing the material used Calorific value. In the latter setup, care must be taken to avoid points of high resistance at junctions made between materials of different composition.

10 and 11 show setups for systems in which the substrate heaters include individually controllable heaters 85 . In the embodiment shown in FIG. 10, the independently controllable heaters 85 are provided as extending members substantially parallel to the main scan axes 181-187 (ie, perpendicular to the scan direction), and the independently controllable heaters 85 are constrained to The geometrical confines of the substrate W are internally heated. However, alternative settings of heaters should also be compatible with embodiments of the present invention, as long as they can be independently controlled. The heating array controller 180 controls each individually controllable heater 85 via an address bus. The heater array controller 180 in turn receives input from a predetermined algorithm 190 which describes how the heat output of each individual heater should be controlled as a function of time (and thus as a function of the sealing member 12 relative to the individual heater under consideration). function of the position of the heater). The use of an appropriate algorithm may be from calibration measurements and/or calculations (eg, based on the amount of time, the expected amount of liquid remaining on the substrate W is expected). This approach has the advantage of not requiring a temperature sensor, which greatly simplifies construction.

Evaporation of the immersion liquid may also lead to cooling of the sealing member 12 itself. This effect in turn leads to cooling of the substrate W, for example by cooling the immersion liquid and/or the pressurized gas, by convection, and/or by radiation effects. According to an aspect of the present invention, a sealing member temperature stabilizer is provided to reduce cooling of the substrate W by this mechanism.

The areas concerned in particular are located around the vacuum exhaust inlet 17 and in the vacuum exhaust line 14 . The impregnating liquid is present in these areas, in particular net evaporation occurs when the vapor concentration is kept low by the vacuum system (evaporating liquid is immediately pumped away). One way in which the overall cooling of the sealing member 12 can be controlled due to this mechanism is depicted in FIG. Thermal isolation sleeve 210 is preferably formed from a material that has low thermal conductivity at the expected operating temperature of the lithographic apparatus. General purpose plastics, PTFE, etc. are suitable materials for the thermal isolation sleeve 210 . Alternatively or additionally, the sealing member itself consists wholly or partly of a thermally insulating material. This approach is more efficient and easier to implement than just having the thermal isolation sleeve 210, although the choice of materials with suitable mechanical properties may be limited.

An additional and/or alternative approach is to provide a dedicated seal member heater 220 arranged to provide compensatory heating to those areas of the seal member 12 which are evaporatively cooled by the immersion liquid. While directly heating the sealing member 12 itself on the one hand, and thus indirectly heating the substrate W, the sealing member heater 220 may be provided to heat the substrate W directly. This can be achieved by using radiant emitting heaters such as infrared heaters which have been described above as possible substrate heaters 85/88. In the arrangement shown in FIG. 12, the seal member heater 220 is positioned around the vacuum exhaust inlet and along the vacuum exhaust in a plane perpendicular to the axis of the seal member 12 (into the page in the direction shown). The geometry of the gas inlet.

The heat generation of the seal member heater 220 is controlled by the seal member temperature stabilizer according to one or more inlets from many possible sources. For example, seal member heater power can be adjusted based on the flow rate in the vacuum exhaust line 14 , which can be provided by the pressurized gas supply system 30 . Here, it is hoped that higher heat generation will require higher flow rates.

Seal member heater 220 may also be controlled with reference to the temperature of substrate W and/or substrate table/substrate holder, which may be measured by one or more temperature sensors 60 at one or more locations. As in the previous embodiments, a feedback controller may be employed to reduce the difference between the measured substrate temperature and one or more predefined target temperatures Tt.

Seal member heater 220 may also be controlled in response to the relative humidity of the gas supplied through pressurized gas outlet 18 . This information may be provided by a humidity sensor, which may be provided within the sealing member or as part of the pressurized gas supply system 30 (the latter being illustrated in Figure 13).

Finally, the seal member temperature stabilizer 200 can control the output of the seal member heater 220 with reference to a calibration table 230 requiring correction, established from measurements of the seal member temperature as a function of one or more of the following: substrate temperature, pressurized gas flow rate , pressurized gas flow temperature, vacuum exhaust flow rate, vacuum exhaust temperature, pressurized gas relative humidity and immersion liquid temperature. Although calibration measurements must be undertaken, this approach greatly reduces the need to incorporate additional functional elements in the final lithographic apparatus shipped to the customer.

The most important area of the sealing member 12 is the area closest to and/or facing the substrate W when considering substrate cooling issues associated with a cooled sealing member 12 . According to the embodiment of the invention depicted in FIG. 14 , the sealing member 12 consists of a network of channels distributed in the layer 400 in the portion of the sealing member 12 closest to the substrate W. FIG. The seal member temperature stabilizer 200 is provided to control a heat exchange liquid supply system 410 which provides heat exchange liquid to the network at a controlled temperature and/or flow rate. As described in previous embodiments, a feedback controller can be provided to help control the substrate temperature in a more efficient manner. In such a case, the temperature and/or flow rate of the heat exchange liquid provided by the liquid supply system 400 may be adjusted to reduce the substrate temperature and/or substrate temperature as measured by the local temperature sensor 60 system at one or more The difference between the pedestal temperature and the target temperature Tt. That is, when a single temperature sensor 60 is present, the liquid supply system 400 compares this one temperature reading to a single target temperature Tt, and when there are multiple temperature sensors 60, the liquid supply system 400 compares multiple readings to a single target temperature Tt , or compared to a plurality of target temperatures Tt corresponding to particular regions of the substrate W, and/or corresponding regions of the substrate table/substrate holder, and thus corresponding to temperature sensor readings (which internally may use A special group for average readings). The temperature and/or flow rate of the liquid may be controlled by reference to a calibration table 230 requiring correction, established from measurements of the seal member temperature as a function of one or more of the following: substrate temperature, pressurized gas flow rate, pressurized gas flow temperature, vacuum Exhaust flow rate, vacuum exhaust temperature, pressurized gas relative humidity and immersion liquid temperature. Although calibration measurements must be undertaken, this approach greatly reduces the need to incorporate additional functional elements in the final lithographic apparatus shipped to the customer.

An overall advantage of the embodiments described above relying on mechanical means located in the sealing member 12 is that it can be implemented without affecting the dynamics of the substrate table WT (as is true for liquid-based or electrical systems). The sealing member temperature conditions also improve not only the short-term (die-to-die) temperature variation in the substrate W, but also the long-term temperature variation from one substrate W to the next. More generally, development costs (and development time) associated with sealing member improvements are likely to be significantly lower than those involving substrate table WT. In addition to the issues associated with controlling the power of the substrate table WT, another factor that favors working on the sealing member 12 rather than the substrate table WT involves the flat requirement, which is mitigated by a factor of about 100 for the sealing member 12 as much. It may be important, for example, that channels are machined into the sealing member 12 . As the pressure of the heat exchange liquid changes (due to the reduced hardness of the narrow width of material remaining between the outer surface of the sealing member and the edge of the inner channel), the introduction near the surface (where they are most effective) Pores tend to introduce surface irregularities (bulges).

Figures 15 to 18 depict an arrangement comprising a network of liquid transport channels, this time located close to the substrate W in the substrate table WT. The layout of the channels is arranged to control the temperature of the substrate W, which may be adversely affected by evaporation of the immersion liquid from its top surface.

In this embodiment, a substrate table heat exchange liquid controller 510 is provided for controlling the temperature and flow rate of the heat exchange liquid flowing through the channel network 500 .

As described in previous embodiments, a feedback controller can be provided to help control the substrate temperature in a more efficient manner. In this case, the temperature and/or flow rate of the substrate table heat exchange liquid can be adjusted to reduce the substrate temperature and/or substrate table/substrate temperature measured at one or more systems via local temperature sensors 60. The difference between the holder temperature and the target temperature Tt.

This arrangement can work particularly efficiently if local substrate heaters, such as hot filaments, are also included to implement the "push-pull" temperature control principle. According to this embodiment, the substrate temperature controller 520 controls the operation of the substrate heater controller 430 and the substrate table heat exchange liquid controller 510 . A feedback controller may be included as part of the substrate temperature controller 520 to minimize the difference between the substrate temperature and the target temperature Tt, where the substrate temperature, such as via the local temperature sensor 60 at the substrate W and/or the substrate One or more positions on the stage/substrate holder are measured. That is, where a single temperature sensor 60 is present, the substrate temperature controller 520 compares this one temperature reading to a single target temperature Tt. When multiple temperature sensors 60 are present, the substrate temperature controller 520 compares the multiple readings to a single target temperature Tt, or to multiple target temperatures Tt corresponding to, for example, particular regions of the substrate W, and/or the corresponding area of the substrate table/substrate holder, thus corresponding to a particular set of temperature sensor readings (for which averaged readings may be used internally). Alternatively, if the heat flow can be calculated as a function of the velocity and position of the sealing member 12 relative to the substrate W, a feedforward loop may be used. According to the "push-pull" principle, the heat exchange liquid controller 510 can be set to provide liquid at a temperature lower than the target temperature Tt, effectively cooling the substrate W. A localized substrate heater, which may be a resistive heater (hot filament) as described above, reacts faster to a sudden increase in evaporation rate than the heat exchange liquid controller. Additionally their response speed is improved by setting the cooling action of the heat exchange liquid controller. Also, should an overregulation of the substrate temperature occur, then the supply of cooled heat exchange liquid will return to equilibrium more rapidly than would be the case without the additional cooling mechanism.

For ease of machining (among other reasons), the network of channels 500 comprises an array of vertical holes (which may be drilled) oriented substantially in the plane of the substrate table, as described in FIG. 16 . The ends of these vertical holes must be connected and nearly watertight. This can be done with plugs in these holes. However, in a typical setup including 4mm holes and 8mm pitch, more than 80 plugs may be required. In addition to the problem of needing to build many separate elements, there is the possibility in this arrangement of creating dead ends where the liquid cannot reach or circulate at all. According to an embodiment of the present invention, these problems are overcome by providing a recirculation groove 420 (as shown in FIGS. There are no dead ends. This arrangement has the further advantage that liquid can be circulated closer to the edge of the substrate table WT. The circulation groove 420 can be sealed using a smaller number of components. In the embodiment shown, a seal ring 410 is used, which can be split into two pieces for ease of installation and adhered to the groove by glue or some other standard bonding technique. Improved liquid distribution provides more uniform and controlled cooling of the substrate table WT, resulting in more efficient heat management and improved coverage.

In the above embodiments, it has been shown that the included local substrate temperature sensor 60 is embedded in the substrate table WT close to the substrate W. These sensors can work on several principles, often based on calibrated measurements and repeatable temperature-dependent properties such as electrical resistance. Although shown embedded in the substrate, the localized temperature sensor could also be located in the sealing member 12 as shown in FIG. 19 . Due to the relatively poor thermal connection across the gap 22 (unlike between the substrate W and a sensor embedded in the substrate table WT, where it is easier to provide high thermal conductivity), the sensor 60 located within the sealing member 12 is preferred. It operates by analyzing the radiation emitted from the substrate W. According to an embodiment of the invention, a sensor 60 of this type is provided comprising a radiation capture and analysis device capable of determining the intensity spectrum of the trapped radiation over a range of wavelengths. In general, temperature can be most accurately determined if a wider range of wavelengths is chosen. However, for the temperatures of interest in this application, it is cost-effective to choose a restricted wavelength range that includes and/or is in the middle of the infrared radiation band.

Fig. 20 shows an embodiment of the invention in which a local micro temperature control system 600 is built into the substrate table WT. In the example shown, these control systems 600 are positioned near the top of the raised portion of the substrate table WT (burltops 640 ), which in turn is in contact with the substrate W. Each micro control system 600 includes a micro temperature sensor 610, which may be implemented as a micro energy integrated circuit temperature sensor, and a micro heater 620, which may be implemented as an integrated circuit heater (dissipating heat with resistance). The micro control system 600 is arranged such that the heater element 620 is activated to generate heat when the local temperature of the substrate as measured by the micro temperature sensor 610 drops below a predetermined threshold. Once the temperature rises so that it exceeds a threshold, the micro control system is set to turn off the micro heater. This arrangement has the advantage of being able to provide highly localized temperature control due to the miniature size of the control system 600 and the need for a separate external control system to control the heater 620 . Only two wires (connecting wires 630) will be required to provide voltage to all micro control systems 600 in the substrate table WT. The creation of the micro temperature sensor 600 in the spot top 640 can be done by forming the substrate table WT from a silicon wafer. Micro-fabrication techniques such as MEMS (Micro-Electro-Mechanical Systems) and CMOS (Complementary Metal-Oxide-Semiconductor) technologies can be used to provide a complete replica of the standard substrate table WT configuration, while also adding integrated circuit temperature sensors/ heaters 610/620 and provide a means of electrically connecting them to the outside (connection 630).

FIG. 21 depicts an embodiment of the invention including a projection system controller 710 arranged to adjust properties of a patterned radiation beam based on the substrate and/or substrate table temperature measured by temperature sensor 60 . In the illustrated embodiment, a plurality of temperature sensors 60 are embedded in the substrate table WT. However, it should also be within the scope of the invention to provide the temperature sensor elsewhere, for example within the sealing member 12, and/or to provide only a single temperature sensor.

As mentioned above, evaporation of the immersion liquid on the substrate W may cause cooling of the substrate, and the resulting deformations lead to overlay errors, defocus, chromatic aberration, etc. According to this embodiment, the projection system controller 710 can adjust the parameters of the patterned projection beam, such as its overall scaling, positioning offset, etc., to compensate for the thermally induced deformation of the substrate W. As a simple example, if projection system controller 710 receives input from temperature sensor 60 indicating that substrate W is uniformly at a target temperature to a first approximation, it can be configured to scale the patterned projection beam by a factor to reduce Image size produced on cooled substrate W. When the temperature of the substrate W and/or the substrate table WT is measured by a plurality of temperature sensors 60 to obtain a temperature profile, in order to reduce errors such as stacking errors, defocus and chromatic aberration, more complex corrections can be performed by the projection system controller 710 . This approach provides a rapid method of responding to sudden changes in temperature without the need to incorporate heating elements in the sealing member 12 or the substrate table WT, which would be expensive to perform and/or interfere with the dynamic performance of the substrate table WT. This form of compensation has the added advantage of not needing to rely on special cooling mechanisms to work, and is applicable where changes in the temperature of the substrate W due to processes other than evaporation of the immersion liquid play at least some role.

In the embodiment shown in FIG. 21, a thermally induced deformation calibrator is also provided to transfer the reading from the temperature sensor 60 to the expected deformation of the substrate W. This is obtained by first deriving the temperature profile of the substrate W, and then using known thermal properties of the substrate W, such as the thermal expansion coefficient of the substrate material, to calculate the thermally induced deformation. To a first approximation, the relative deformation of a portion of the substrate W is proportional to the temperature difference between the temperature of that portion and the reference operating temperature (corresponding to zero relative deformation). In the illustrated embodiment, the temperature sensor 60 is embedded in the substrate table WT such that additional calibration is required to derive the substrate temperature profile from the temperature sensor readings. How this can be achieved is described below in this and other embodiments of the invention.

The temperature measurement of the substrate W according to several embodiments described above is determined by a temperature sensor 60 positioned in the substrate table WT. Since there is a relatively large space for the positioning sensors, this arrangement has the structural advantage that they can be positioned robustly and precisely, and that they can be operated more easily via any required electrical connections. As previously discussed, positioning the sensors at a distance from the substrate W in the substrate table WT also provides an efficient means of employing a larger substrate area per sensor 60 . However, it should be understood that the temperature of the material immediately surrounding the temperature sensor 60 can give an approximation of the temperature of the substrate W, and that it is possible to obtain a more accurate map of the substrate temperature profile by further analysis described below. This analysis may be performed as part of any of the embodiments described above that include a temperature sensor 60 located within the substrate table WT.

Assuming that the heat transfer from the substrate surface to the horizontal plane in the substrate table WT with the temperature sensor 60 therein can be described as:

${\mathrm{<span\; class="notranslate">\; T</span>}}_{<span\; class="notranslate">\; \&infin;</span>}^{\mathrm{<span\; class="notranslate">\; chuck</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; current</span>}}^{\mathrm{<span\; class="notranslate">\; chuck</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; substrate</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

where T _∞ ^chuck is the initial temperature of the substrate W, T _current ^chuck is the current temperature of the region of the substrate measured by the sensor 60 embedded in the substrate table WT, and ΔT ^substrate is the temperature for the region in question Temperature difference at substrate level. On the basis of this relationship the temperature of the region of the substrate as a whole (if desired) and a temperature profile for the substrate can be derived. For example, the following model can be used:

${\mathrm{<span\; class="notranslate">\; T</span>}}_{<span\; class="notranslate">\; \&infin;</span>}^{\mathrm{<span\; class="notranslate">\; chuck</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; current</span>}}^{\mathrm{<span\; class="notranslate">\; chuck</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; .</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; substrate</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}}<span\; class="notranslate">\; ,</span>$

followed by:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; substrate</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{<span\; class="notranslate">\; \&infin;</span>}^{\mathrm{<span\; class="notranslate">\; chuck</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; current</span>}}^{\mathrm{<span\; class="notranslate">\; chuck</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

It provides an expression for the temperature difference at the substrate level based only on the parameters τ and k, which in turn can be estimated from test data.

A similar analysis can be used to derive a better measure of substrate temperature from the infrared temperature sensing signal. Here, the problem is that silicon (which is often used as the substrate material) is transparent to infrared rays, so an infrared sensor positioned in the sealing member 12 "looking down" on the substrate W will receive signals from the substrate W and The mixing of the radiation emitted by the substrate table WT directly below it.

As described above, as the sealing member 12 moves relative to the substrate W, a thin film of liquid may be left on the top surface of the substrate W in the wake of the sealing member 12 . Evaporation of these liquids can extract heat from the substrate W and/or substrate table WT if sufficient effective measures are not taken. The resulting decrease in the temperature of the substrate W and/or substrate table WT can lead to shrinkage, which in turn can lead to overlay errors, overall loss of performance/resolution/and loss of yield of the integrated circuit to be produced . Several solutions to this problem are discussed above, including providing a network of substrate heating channels and/or an array of independently controlled electric heaters. However, it is difficult to tune the operation of these heating mechanisms in such a way that heat is only generated where evaporation occurs. Therefore, it is difficult to ensure that temperature gradients within the substrate W are minimized.

According to an embodiment of the present invention, there is provided a lithographic apparatus having means for heating the immersion liquid remaining in the wake of the sealing member 12 using microwave radiation. The frequency of the microwave radiation is tuned to primarily heat the immersion liquid directly without coupling to surrounding equipment elements (eg, substrate table WT, substrate W, sealing member 12, etc.). Heat can thus be applied directly and precisely where it is needed, while temperature gradients can be minimized. In general, the heat needed to evaporate the liquid can be provided entirely by the microwave source, so that no heat is drawn from the substrate W.

Figure 22 shows an example setup comprising a microwave source 800 arranged to provide microwave radiation for heating the immersion liquid used, and a microwave vessel cover 810 designed to contain the microwave radiation within a region of interest (for a protected region, e.g. Immersion liquid container 25, where heating is undesirable). In the illustrated embodiment, the region of interest substantially covers an annular region of the substrate W around the sealing member 12 . The size of the area covered by the microwave container cover 810 may be chosen to be sufficiently large that the microwave radiation can completely evaporate before the sealing member 12 moves far enough relative to the substrate table WT that the liquid will remain in the area exposed to the microwaves. The immersion liquid remaining in the wake of the sealing member 12 . The dimensions of the microwave enclosure 810 will thus be a function of the intensity of microwave radiation remaining in the enclosure 810 , the speed at which the sealing member 12 passes the substrate table WT, and the amount of liquid expected to remain in the wake of the sealing member 12 .

Microwave container cover 810 may be formed of a metallic material with appropriately sized openings to ensure substantially total reflection of microwaves. The propagation of microwave radiation within the microwave container cover 810 is schematically shown by arrow 830 . The power of the microwave source 800 can be selected based on calibration measurements, which determine the rate at which liquid remaining on the substrate is heated. For example, many different microwave source powers were tested in order to determine which power source resulted in the smallest overlay error. Optionally, a temperature sensor 60 may be provided and incorporated into the feedback loop via data connection 850 . This arrangement is advantageous when the speed of the sealing member 12 changes over time and/or when the amount of immersion liquid escaping from the sealing member 12 changes. Feedback mechanisms are also useful when microwave heating devices are used in conjunction with other temperature compensation methods, which effectively change over time. In a feedback arrangement as described above, the feedback loop here may include adjusting the power of the microwave source 800 so that the temperature measured by the temperature sensor 60 converges towards one or more target temperatures. It is expected that microwave source 800 will emit microwave wavelength radiation. However, if the wavelength of the radiation most efficiently coupled to the immersion liquid used is just outside the usual wavelength range associated with microwaves, it will be appreciated that the source 800 is adapted to emit radiation of an appropriate wavelength (eg in the infrared or in the visible).

Figure 23 shows a substrate heater setup that enables adjustment of spatial variation in heat output based on spatial variation in substrate temperature without requiring complex setup of temperature sensors and/or external control systems. This can be achieved by forming a conductive strip 900 close to the surface of the substrate table WT, in good thermal contact with the substrate W. For example, the conductive strip 900 may be formed by coating a conductive material on the top surface of the substrate table WT. In the illustrated embodiment, an external current source 920 (not shown) is provided such that an equal current 910 passes through each conductive strip 900 . According to a first variant, a single current source 920 provides the same current through each conductive strip 900 . Alternatively, multiple current sources 920 may be provided, arranged to pass different currents through the conductive strip 900 . In another case, the current through each strip 900 is held constant so that the rate of heat generated by resistive heating per unit length depends only on the local resistance of the material forming the strip 900 . According to this embodiment, the material is chosen to have a negative temperature dependence (ie, an increase in temperature results in a decrease in resistance), preferably a strong negative temperature dependence, so that in the cooler regions of each conductive strip 900 (which has a higher resistance) significantly more heat is generated than in relatively hotter regions. In this case, more heat is naturally directed to those areas that need it most, thus reducing temperature gradients. In particular, the current 910 can be varied until the difference in heat generation between the cooler and hotter regions substantially compensates for the heat removed by evaporation of the liquid on the surface of the substrate W (which, as described above, is desirable for substrate W The non-uniformity of the bottom temperature makes the main contribution). The heat generated at any given segment of one of the conductive strips is expected to be proportional to the square of the current multiplied by the resistance of that segment.

In the embodiments described above, the temperature dependent resistivity of the conductive tape 900 is used directly to provide a temperature dependent substrate which is heated by using the conductive tape itself as a heater. According to an alternative embodiment of the present invention, the conductive strips 900 may be used as temperature sensors, which may be combined with their function as heating elements. Figure 24 shows the setup according to this embodiment. Again, current 910 is passed through conductive strip 900, which is configured to have a temperature dependent resistivity. Preferably, the temperature-dependent resistance is strongly negative, as previously stated, but weaker temperature dependencies and/or positive temperature dependencies can also be tolerated. According to this embodiment, separate localized substrate heaters 930 are provided, each powered by a localized power supply/amplifier 950 . Power to each substrate heater 930 is controlled by reference to measurements of local resistivity in the segment of conductive tape 900 closest to the substrate heater 930 in question. This can be obtained, for example, by measuring the potential difference between the nearest pair of electrodes 940, as shown in FIG. 24 . As previously mentioned, the local resistivity of the conductive strip 900 is a function of the local temperature.

Calibration measurements can be used to determine the relationship between the resistivity and the local temperature of the substrate W, and the power supply/amplifier 950 can be set to adjust based on the difference between the measured resistivity and the resistivity corresponding to the desired temperature. Substrate heater 930 power.

The above arrangement has the advantage of not being limited by the strength of the temperature dependence of the resistivity of the conductive strip 900 and can provide mainly more intense spatially dependent heating energy to the substrate W. Providing a large number of power supply/amplifier 950 and substrate heater 930 pairs allows high spatial resolution. In addition, since the heating energy provided to the substrate heater 930 is determined by a simple measurement of the resistivity near the section of the conductive tape 900, there is no need for complex and bulky electronics at the substrate table plane or complex control electronics provided externally. equipment. The amplification factor (or amplification function: describing how the local heater power should vary with offset from the desired temperature) provided by the power supply/amplifier 950 can be predetermined with reference to calibration measurements and can be provided in hardware.

Figure 25 shows an embodiment of the present invention in which the substrate W is heated by an induction heater. This approach has the advantage of providing heating primarily where it is needed (eg around the seal member 12). The inductive source 960 is activated to provide inductive heating energy by coupling with an inductive element 970 formed inside the substrate table WT, and is preferably positioned to make good thermal contact with the substrate WT. The power output of the induction source 960 is in turn controlled by the induction controller 980 . The induction controller 980 may vary the energy of the induction source 960 according to a predetermined route (eg, to primarily heat the area of the substrate W over which the sealing member 12 has most recently passed). Multiple spatially separated induction sources and/or elements may be provided: for example, each may be configured to provide the same or a different amount of heating so that the substrate W may be provided with heat in a manner that reduces temperature gradients. Alternatively, the inductive controller 980 may use a feedback model. This may be configured to vary the output power of the inductive source 960 such that the temperature measured by one or more temperature sensors 60 converges with one or more corresponding target temperatures. The use of induction heating to heat the substrate table WT has the additional advantage that only minor changes to the substrate table WT (eg, adding inductive elements 970 ) are required. Therefore, the mechanical operation of the substrate table WT is not significantly disturbed. The fact that the sensing source 960 is mechanically separated from the sensing element 970 is advantageous, also in terms of upgradeability: each element is adapted to a large extent independently of the other.

As mentioned above, one way to reduce the cooling caused by the evaporation of the immersion liquid from the surface of the substrate W is to provide the gas seal 27 with a humid gas (a humid gas is broadly understood as the gas). The gas on the substrate W contains a higher proportion of impregnating liquid vapor, establishing a dynamic equilibrium between the evaporation of the liquid from the substrate W and the condensation of the liquid vapor onto the substrate W, such that the net evaporation rate is lower than if the substrate W The gas above W is a dry condition (ie does not contain any substantial amount of impregnating liquid vapor). In order for this mechanism to work in a repeatable and constant manner, it is necessary to provide a reliable means of humidifying the gas supplied to the gas seal 27 . According to an embodiment, as schematically shown in Fig. 26, a humidification element 1000 is provided for this purpose. Gas is input into humidification component 1000 from a source of clean gas, for example, via conduit 1005 to evaporation vessel 1010 . The evaporation vessel 1010 includes internal heating elements that heat one or more immersion liquid containers in order to generate immersion liquid vapor. The resulting impregnating liquid vapor is mixed with clean gas supplied via conduit 1005 and output from evaporation vessel 1010 via conduit 1015 . The partially saturated gas is then fed into condensing vessel 1020 (also referred to as "cooling vessel") where it is cooled to the point that the mixture of gas and impregnating liquid vapor becomes supersaturated and the impregnating liquid condenses out of the mixture. What remains in gaseous form is the impregnating liquid vapor that is very close to or just 100% saturated at the operating temperature of the condensation vessel 1020 . This 100% saturated gas supply is then input via conduit 1025 into mixing chamber 1040 where it can be mixed with a dry gas source input via conduit 1035 from dry gas source 1030 in a controlled ratio such that the output gas is passed through conduit 1045 to The controlled temperature and/or controlled saturation output, for example, may then be supplied to the gas seal 27 .

An alternative system for humidifying the gas is to pass it through a so-called bubbler, which is a porous device immersed in a container containing liquid and liquid vapor. The gas becomes progressively saturated as it passes. Controlling the saturation or humidity of the gas produced is difficult in this setup. Changes in flow rate, vessel temperature, or liquid level can affect the amount of liquid vapor retained in the gas leaving the system. In particular, it is difficult to achieve 100% saturation using this method. Optimizing the performance of such systems can result in relatively complex device designs, eg ensuring adequate and repeatable contact between liquid and gas.

As mentioned above, evaporation of the immersion liquid from the substrate W has detrimental effects on the performance of the lithographic apparatus. Contamination in the liquid can lead to particle contamination (also referred to as water contamination) on the substrate W. Evaporation can also adversely affect coverage performance, focus and optical performance because of cooling effects. Humidified gas in the gas seal 27 may be used to minimize evaporation. According to one approach, 100% saturated gas is required to achieve zero net evaporation from the surface of the substrate W. Embodiments in which 100% saturated gas is produced in a controlled manner have been discussed above. However, due to the expansion of the gas, as it exits the gas seal 27, the relative humidity of the gas inevitably decreases. In practice, this may mean that when the gas is drawn at the operating temperature of the substrate W (eg 22° C.), the near-use maximum achievable humidity may be substantially below 100%, eg about 60%. If a gas with less than 100% relative humidity remains above the substrate surface, some degree of net evaporation will occur.

According to an embodiment schematically illustrated in Figure 27, the humidity of the gas is controlled by increasing the temperature of the gas supplied to the gas seal after the gas has left the gas seal 27 and has expanded.

In this case, the hot gas leaving the gas seal 27 is suddenly exposed to a lower temperature environment (ie, the normal operating temperature of the lithographic apparatus) and cooled. Cooling tends to increase saturation or relative humidity. The overall temperature drop can be controlled to compensate for the expansion of the gas and the associated decrease in saturation rate.

For a typical system maintained at an operating temperature of 22°C and with near-saturated (eg 90-100% relative humidity) gas supplied to the gas seal 27, a typical seal member pressure drop of 0.4 bar, between 1 and 5K The temperature offset is sufficient to maintain close to 100% relative humidity in the gas remaining above the substrate W outside the gas seal 27 . Careful design of the system is required to prevent condensation of highly saturated gas before the gas leaves the gas seal 27 . For example, the conduit wall leading through the seal member 12 to the gas seal 27 should be thermally insulated to isolate hot gas from the cooled seal member 12 and prevent condensation on the conduit wall.

FIG. 27 , as described above, shows an arrangement for controlling the temperature of the gas supplied to the gas seal 27 , which may be located, for example, between the humidification component 1000 and the gas seal 27 . The associated cooled saturated gas is supplied through conduit 1045 to heat exchanger 1100 which heats the saturated gas to a target temperature by heat exchange with heat exchange liquid provided by heater 1110 . Heater 1110 provides heat exchange liquid through input line 1120 at temperature T1 and receives heat exchange liquid through input line 1130 at temperature T2, where T1 is greater than T2. For example, the heater 1110 may heat the heat exchange liquid via a Peltier heater. According to an example setup, a Peltier heater is provided that operates in the range of 500 watts to 1500 watts to produce water that is temperature controlled to a 27°C set point to within ±0.01°C.

According to an embodiment of the invention briefly described in Figure 28, a humidification cabinet 1200 is used to generate a high-purity flow of humid gas, where several parallel evaporation units 1220 are used to evaporate the liquid. The temperature of the generated humidified gas is controlled by providing each evaporator 1220 with a flow of temperature-controlled heat exchange liquid via conduit 1205 . Heat exchange liquid may be provided by heat exchange liquid source 1110 and may also be used to control the temperature of the saturated gas prior to supply to gas seal 27 as described above. Alternatively, a separate source of heat exchange liquid may be provided. The humidity and temperature controlled gas passes through the hydrophobic filter 1210 to the output valve 1250 before passing through the heat exchanger 1100 to the sealing member 27 .

Changing or even stopping the humidified gas flow from the humidification cabinet 1200 changes the balance, and a long stabilization time may be required before the humidified gas flow is supplied to the gas seal 27 again at a well-controlled temperature and saturation. However, due to the dynamic nature of the tasks performed by the sealing member 12 and the gas seal 27, the gas rate required by the gas seal 27 may vary considerably over time: for example, there may be short periods of time when the gas seal 27 is not functioning. In addition to adjusting the system so that it stabilizes more quickly, which requires robust and complex extras, this embodiment includes a variable ventilation system 1240 that allows gas to be vented to and out of the outer container at a controllable rate. The ventilation system 1240 can be arranged such that the flow rate from the humidification cabinet 1200 remains constant. This is actually achieved by ensuring that the overall flow rate through the main valve 1250 and ventilation system 1240 remains constant. This can be implemented by setting the ventilation system 1240 to have a flow resistance corresponding to the reading of the pressure gauge 1230 , which corresponds to the back pressure "felt" by the humidification cabinet 1200 . In particular, this pressure should be kept constant. This arrangement not only provides better stability, but also higher throughput, since the need for stabilization times between different operating phases of the gas seal 27 can be avoided.

All of the above features can be combined in any combination and can be applied in connection with all types of liquid supply systems including those mentioned in the background section above.

Although a specific description is made herein of the use of lithographic apparatus in IC fabrication, it should be understood that the lithographic apparatus described herein may have other applications, such as the fabrication of integrated optical systems, pattern guidance for magnetic domain memories and Inspection, flat panel display, liquid crystal display (LCD), thin film magnetic head, etc. It should be clear to those skilled in the art that, in the preceding paragraphs of alternative applications, any use of the terms "wafer" or "die" herein is considered synonymous with the more general terms "substrate" or "target portion", respectively. The substrate here can be processed, before or after exposure, in eg a track (typically a tool that applies a layer of resist to a substrate and develops the exposed resist), a metrology tool and/or a viewing tool. Applicable, the disclosure herein may be applied to such or other substrate processing tools. Also, a substrate may be processed more than once, for example in order to create a multilayer IC, so that the term substrate as used herein may also refer to a substrate that already contains multiple processed layers.

Although specific reference has been made above to embodiments of the invention in the context of utilizing lithography, it will be appreciated that the invention may also find application in other applications, such as printing lithography, and is not limited to lithography as the context permits. In printing lithography, the shapes in the patterned device define the pattern produced on the substrate. The shape of the patterned device can be imprinted into a resist layer provided to the substrate where the resist is hardened by application of electromagnetic radiation, heat, pressure or a combination thereof. After the resist has hardened, the patterned device is removed from the resist leaving a pattern in it.

The terms "radiation" and "beam" as used herein include all types of electromagnetic radiation, including ultraviolet (UV) radiation (i.e. having a wavelength of about 365, 248, 193, 157 or 126 nm) and extreme ultraviolet (EUV) radiation (e.g. have a wavelength in the range of 5-20nm), and particle beams, such as ion beams or electron beams.

The term "lens", as permitted herein, refers to any one or combination of types of optical elements, including refractive, reflective, magnetic, electromagnetic, and electrostatic optical elements.

While specific embodiments of the invention have been described above, it should be understood that the invention can be practiced otherwise than as described. For example, the present invention may take the form of a computer program comprising one or more sequences of machine-readable instructions describing the methods disclosed above, or a data storage medium (such as a semiconductor memory, magnetic or optical disk) having such a computer program stored thereon. ).

The invention may be applied to any immersion lithographic apparatus, in particular, but not exclusively, to those types described above.

The above description is intended to be illustrative rather than restrictive. Accordingly, modifications may be made to the invention as described by a person skilled in the art without departing from the scope of the following claims.

Claims (63)

1. A lithography equipment, comprising: Lighting systems that regulate radiation beams; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; a substrate table supporting the substrate; a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; a liquid supply system for at least partially filling the gap between the last element of the projection system and the substrate with liquid; a gap between said final element of the projection system and said substrate substantially contains said liquid sealing means; and a liquid evaporation controller that controls the net rate of evaporation of liquid provided by said liquid supply system. 2. The lithographic apparatus of claim 1, further comprising a gas seal connected to a gas source, which controls passage of a gap from the second side of the substrate on one side of the boundary of the sealing member to the second side of the substrate. The amount of liquid that escapes the sealing member, wherein the liquid evaporation controller includes a gas humidity controller that interacts with the gas source to provide the gas with a controlled relative humidity of greater than 10%. 3. The lithographic apparatus of claim 2, wherein the gas humidity controller is configured to generate a flow of humidity-controlled gas at a constant flow rate, and the gas source comprises a gas-tight flow rate controller configured to into receiving a constant gas flow from the humidity controller and varying the gas flow rate by selectively exhausting a portion of the constant gas flow provided by the humidity controller to an external container. 4. The lithographic apparatus of claim 2, wherein the humidity controller comprises a humidification component for humidifying the gas to a controlled degree, the humidification component comprising: an evaporation vessel receiving a relatively dry gas stream and at least partially humidifying said gas stream with liquid vapor evaporated from at least one tank; and A cooling vessel, controlled at a temperature substantially lower than that of the evaporation vessel, receives and cools said at least partially moist gas stream to obtain a fully saturated gas stream. 5. The lithographic apparatus of claim 4, wherein the humidification unit further comprises a dry gas source connectable to the saturated gas output of the condensation vessel, wherein the gas humidity controller is capable of regulating the dry gas The proportion mixed with the saturated gas stream output from the condensing vessel to obtain a gas stream with controlled relative humidity. 6. The lithographic apparatus of claim 2, wherein the gas source includes a gas temperature controller that interacts with the gas source to control the temperature of the gas supplied to the gas seal, wherein the gas enters The temperature before sealing is set higher than the average temperature of the substrate. 7. The lithographic apparatus of claim 6, wherein the temperature of the gas before entering the gas seal is set between 1 and 5 K above the average temperature of the substrate. 8. The lithographic apparatus of claim 6, wherein the temperature of the humid gas supplied to the seal reaches a desired level of humidity after expansion in the gas seal. 9. The lithographic apparatus of claim 2, wherein the gas source provides gas with a relative humidity greater than 40%. 10. The lithographic apparatus according to claim 2, further comprising: at least one temperature sensor for measuring the temperature at at least a portion of at least one of the substrate, the substrate table, and the substrate holder, wherein The humidity controller is capable of adjusting the relative humidity of the gas provided by the gas source to reduce the difference between the temperature measured by the at least one temperature sensor and at least one target temperature. 11. The lithographic apparatus of claim 1, wherein said evaporation controller comprises a gas shower outlet for supplying a gas of a controlled relative humidity in excess of 10% to an outer region of said sealing member, said sealing member between the substrate and the final element of the projection system. 12. The lithographic apparatus according to claim 11, wherein the gas shower outlet is arranged to provide gas with a relative humidity in the range of 40% to 50%. 13. The lithographic apparatus according to claim 11, further comprising: at least one temperature sensor for measuring the temperature at at least a portion of at least one of the substrate, the substrate table, and the substrate holder; and A gas shower outlet controller capable of adjusting the relative humidity of the gas supplied by the gas shower outlet to reduce the difference between the temperature measured by the at least one temperature sensor and at least one target temperature. 14. The lithographic apparatus according to claim 1, further comprising: a gas seal connected to a gas source for controlling the amount of liquid escaping from said sealing member through a gap defined on one side by a boundary of said sealing member and on a second side by said substrate , wherein the gas source provides a gas with a controlled relative humidity in excess of 10%; and providing a gas shower outlet of a controlled relative humidity substantially equal to that provided by said gas source to an outer region of said sealing member between said substrate and a final element of said projection system The relative humidity of the gas. 15. A lithography apparatus, comprising: Lighting systems that regulate radiation beams; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; a substrate table supporting the substrate; a projection system for projecting the patterned radiation beam onto a target portion of the substrate; a liquid supply system for at least partially filling the gap between the last element of the projection system and the substrate with liquid; a sealing member substantially containing said liquid in said gap between said final element of a projection system and said substrate; and a substrate table displacement system that moves the substrate table along a predetermined path relative to the sealing member, thereby moving the target portion on the surface of the substrate; and A microwave source and microwave container means, together, are arranged to provide heat to the liquid on the surface of the substrate. 16. A lithographic apparatus according to claim 15, wherein said microwave container means comprises a metal enclosure and defines a volume in which microwave radiation generated by said microwave source propagates. 17. The lithographic apparatus of claim 15, wherein said microwave container device is fixed relative to said sealing member, at any time said volume extends to cover only a subsection of said substrate surface around said sealing member. area. 18. A lithography apparatus, comprising: Lighting systems that regulate radiation beams; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; a substrate table supporting the substrate; a projection system for projecting the patterned radiation beam onto a target portion of the substrate; a liquid supply system for at least partially filling the gap between the last element of the projection system and the substrate with liquid; a gap between said final element of the projection system and said substrate substantially contains said liquid sealing means; and a substrate table displacement system that moves the substrate table along a predetermined path relative to the sealing member, thereby moving the target portion on the surface of the substrate; and A substrate heater for heating at least a portion of the substrate based on at least one of position, velocity, acceleration, and predetermined path of the substrate table relative to the sealing member, local substrate temperature, and local substrate table temperature . 19. The lithographic apparatus of claim 18, wherein the substrate heater comprises at least one of the following: an induction heater, a visible light source, an infrared emitting source, a hot filament resistive heater, and a temperature controlled gas injector. 20. The lithographic apparatus of claim 19, wherein the induction heater is arranged to heat the substrate across an induction plate associated with the substrate table and formed of a material suitable for induction heating. 21. The lithographic apparatus of claim 18, wherein said substrate heater comprises a plurality of localized heaters, each capable of substantially heating a separate portion of a substrate, wherein said localized heaters are arranged so that when positioned to Switching to a heating state when heating an area of the substrate that the sealing member has passed and switching to a non-heating state when positioned to heat an area of the substrate that the sealing member has not passed. 22. The lithographic apparatus according to claim 18, further comprising substrate table path determination means for determining at least one of position, velocity, acceleration and a predetermined path of said substrate table. 23. The lithographic apparatus of claim 18, wherein the substrate heater comprises a plurality of remote heaters located around the circumference of the sealing member. 24. The lithographic apparatus of claim 23, wherein the energy output of the remote heater is controlled in dependence on the direction of movement of the sealing member relative to the substrate table, as determined by the substrate table path determining means . 25. The lithographic apparatus of claim 24, wherein the remote heater located closest to the leading edge of the sealing member provides lower power than the remote heater located closest to the trailing edge of the sealing member output. 26. The lithographic apparatus according to claim 23, further comprising at least one temperature sensor for measuring the temperature of at least a portion of at least one of the substrate, the substrate table, and the substrate holder; and A substrate temperature controller for controlling the output of each of the plurality of remote heaters so as to reduce a difference between the temperature measured by the at least one temperature sensor and at least one target temperature. 27. The lithographic apparatus according to claim 26, wherein at least one of said at least one temperature sensor comprises a radiation capture and analysis device capable of determining an intensity spectrum of trapped radiation in a wavelength range including infrared. 28. The lithographic apparatus according to claim 18, wherein said substrate heater comprises at least one localized heater primarily heating a different portion of said substrate, said lithographic apparatus further comprising: at least one temperature sensor for measuring the temperature of at least a portion of at least one of the substrate, the substrate table, and the substrate holder; and A substrate temperature controller for controlling the output of the at least one local heater to reduce a difference between the temperature measured by the at least one temperature sensor and the target temperature. 29. The lithographic apparatus of claim 18, wherein said substrate heater comprises an immersion liquid temperature controller arranged to interact with said liquid supply system to control filling of said final element and The temperature of the liquid in the gap between the substrates, wherein the liquid has a temperature greater than 295K. 30. The lithographic apparatus of claim 18, further comprising: a gas seal arranged to control the amount of liquid escaping from said sealing member through a gap defined by a boundary of said sealing member on one side and Confined on the second side by the substrate, the gas seal is supplied with pressurized gas via a pressurized gas supply system, wherein the substrate heater includes a pressurized gas supply system that interacts with the controlled supply to A gas temperature controller for the temperature of the pressurized gas of the gas seal, wherein the gas has a temperature greater than 300K. 31. The lithographic apparatus according to claim 18, wherein said substrate heater is arranged to provide a higher The amount of heating is provided with progressively lower amounts of heating at target areas on the same substrate on which the projection system subsequently projects the patterned radiation beam. 32. The lithographic apparatus according to claim 28, wherein said at least one localized heater is arranged to substantially follow a predetermined path of said sealing member relative to said substrate table. 33. The lithographic apparatus according to claim 31, wherein said substrate heater comprises elongate elements arranged in substantially parallel strips, said strips being oriented substantially perpendicular to the direction of said sealing member relative to said substrate table. In the scanning direction, the spacing of the bands is set to increase progressively from a first band corresponding to the region of the substrate in which the projection system projects the radiation beam during the first time, to a last band, the last band Corresponds to the region of the same substrate in which the projection system projects the radiation beam during a time period subsequent to the first time period. 34. The lithographic apparatus of claim 33, wherein each of said parallel strips provides a uniform energy per unit length along its length. 35. The lithographic apparatus according to claim 31, wherein said substrate heater comprises elongated elements arranged in substantially parallel strips, said strips being oriented substantially perpendicular to the direction of said sealing member relative to said substrate table. A scan direction in which the strips are arranged to provide progressively decreasing energy per unit length from a first strip to a final strip with the substrate on which the projection system projects the radiation beam during the first time Corresponding to regions, this last band corresponds to regions of the same substrate where the projection system projects said radiation beam during a time period subsequent to the first time period. 36. The lithographic apparatus of claim 18, wherein said substrate heater comprises an array of individually addressable local heaters and heaters adapted to control activation of said individually addressable local heaters according to a predetermined algorithm. The array controller, the predetermined algorithm controls activation with respect to at least one of: heater position, timing, heat generated, and rate of heat generated. 37. The lithographic apparatus according to claim 18, wherein said substrate heater comprises: at least one conductive strap in good thermal contact with a portion of the substrate; and a current source passing a controlled amount of electrical current through the at least one conductive strip; wherein: The resistivity of the conductive strips is selected such that the resistive heating from the current in relatively cool regions of the substrate is higher than the resistive heating of the current in relatively hot regions of the substrate . 38. The lithographic apparatus according to claim 37, wherein said amount of current minimizes temperature gradients caused by evaporation of liquid from the surface of the substrate. 39. The lithographic apparatus of claim 37, wherein said at least one conductive strip is formed of a material having a resistance that decreases with increasing temperature. 40. The lithographic apparatus according to claim 37, further comprising a plurality of localized substrate heaters, each configured to provide heat to a localized subregion of the substrate; at least one local substrate heater controller for controlling the output power of at least a subset of the plurality of local substrate heaters; and a plurality of resistivity measuring devices, each configured to measure the resistivity of at least a portion of at least one of said conductive strips; wherein The output power of each of said localized substrate heaters is controlled based on the resistivity of a portion of the conductive strip closest to the localized sub-region to be heated and measured by one of said resistivity measuring devices. 41. The lithographic apparatus according to claim 40, further comprising: a constant current source passing a controlled amount of current through at least one of said conductive strips; and wherein The resistivity measuring device operates by measuring a potential difference induced between at least two points of each conductive strip. 42. A lithography apparatus, comprising: Lighting systems that regulate radiation beams; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; a substrate table supporting the substrate; a projection system for projecting the patterned radiation beam onto a target portion of the substrate; a liquid supply system for at least partially filling the gap between the last element of the projection system and the substrate with liquid; the gap between said final element of the projection system and said substrate substantially contains said liquid sealing means; a gas seal that controls the amount of liquid escaping from said sealing member through a gap defined on one side by a boundary of said sealing member and on a second side by said substrate; The gas seal includes a pressurized gas outlet through which pressurized gas is supplied to the region within the gap, and a vacuum exhaust inlet through which gas supplied by the pressurized gas outlet is discharged from the region within the gap Alternatively, the pressurized gas outlet and the vacuum exhaust inlet are respectively connected to a pressurized gas pipe and a vacuum exhaust pipe embedded in the sealing member, wherein the sealing member further includes a sealing member temperature stabilizer. 43. A lithographic apparatus according to claim 42, wherein said sealing member temperature stabilizer comprises a thermal isolation sleeve for providing substantial thermal isolation between said vacuum exhaust tube and said sealing member . 44. The lithographic apparatus of claim 42, wherein said seal member temperature stabilizer comprises a seal member heater positioned adjacent to said vacuum exhaust inlet and having at least a portion in a direction perpendicular to the axis of said seal member. substantially follows the geometry of the vacuum exhaust inlet in the plane. 45. The lithographic apparatus according to claim 44, wherein said seal member temperature stabilizer further comprises a seal member heater controller which is based on a flow rate in said vacuum exhaust pipe, a flow rate in said pressurized gas pipe, At least one of flow rate and relative humidity of gas provided by the pressurized gas inlet controls the output of the seal member heater as measured by a gas seal gas supply control unit. 46. The lithographic apparatus according to claim 45, further comprising at least one temperature sensor for measuring the temperature of at least a portion of at least one of said substrate, said substrate table and substrate holder, wherein said sealing member A temperature stabilizer is arranged to reduce the difference between the temperature measured by the at least one temperature sensor and at least one target temperature. 47. The lithographic apparatus according to claim 42, wherein said seal member temperature stabilizer controls the output of said seal member heater with reference to a calibration table established from measurements of seal member temperature as at least one of function of: substrate temperature, substrate table temperature, pressurized gas flow rate, pressurized gas flow temperature, vacuum exhaust flow rate, vacuum exhaust temperature, pressurized gas relative humidity, and immersion liquid temperature. 48. The lithographic apparatus of claim 42, further comprising a network of channels disposed in said sealing member adjacent to a boundary of said sealing member closest to said substrate table, wherein said sealing member temperature stabilizer A heat exchange liquid supply system is arranged to control to provide liquid to the network at a controlled temperature and flow rate. 49. A lithography apparatus comprising: Lighting systems that regulate radiation beams; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; a substrate table supporting the substrate; a projection system for projecting the patterned radiation beam onto a target portion of the substrate; a liquid supply system for at least partially filling the gap between the last element of the projection system and the substrate with liquid; a sealing member substantially containing said liquid in a gap between said final element of the projection system and said substrate; A substrate table heat exchange liquid controller for controlling the temperature and flow rate of the heat exchange liquid flowing through the channel network embedded in the substrate table. 50. A lithographic apparatus according to claim 49, wherein said network of channels comprises: an array of substantially rectilinear holes oriented in the plane of the substrate table, each arranged to open into the periphery of said substrate table In the surrounding trench provided near the edge, the lithographic apparatus further comprises: Substrate table channel closing members are cooperatively securable into the surrounding trenches to connect the substantially rectilinear holes together to form the channel network. 51. The lithographic apparatus according to claim 49, further comprising: at least one temperature sensor for measuring the temperature of at least a portion of at least one of the substrate, the substrate table and the substrate holder, wherein the heat exchange liquid controller is configured to control the temperature of the heat exchange liquid at least one of temperature and flow rate to reduce the difference between the target temperature and the temperature measured by each of the at least one temperature sensor. 52. The lithographic apparatus according to claim 51, further comprising: at least one local substrate heater and a local substrate heater controller for controlling the output of said at least one local substrate heater to reduce The difference between the measured temperatures. 53. A lithography apparatus comprising: Lighting systems that regulate radiation beams; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; a substrate table supporting the substrate; a projection system for projecting the patterned radiation beam onto a target portion of the substrate; The substrate table includes at least one integrated local temperature control system comprising: A temperature sensor coupled to a heater configured to generate heat when the local temperature measured by the temperature sensor is below a predetermined reference value and to cease generating heat when the local temperature exceeds the predetermined reference value. 54. A lithographic apparatus according to claim 53, wherein said substrate table comprises a support member formed from a silicon wafer, comprising a raised portion in contact with and supporting said substrate, wherein said temperature sensor and said A heater is positioned in the riser. 55. A lithography equipment comprising: Lighting systems that regulate radiation beams; a support supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; a substrate table supporting the substrate; a projection system for projecting the patterned radiation beam onto a target portion of the substrate; at least one temperature sensor for measuring the temperature of at least a portion of at least one of the substrate, the substrate table, and the substrate holder; and a projection system controller that adjusts properties of the patterned radiation beam based on the temperature measured by the at least one temperature sensor. 56. The lithographic apparatus according to claim 55, wherein said at least one temperature sensor is embedded in said substrate table, said projection beam controller comprising a thermally induced deformation calculator arranged to calculate the temperature and hence from said substrate table. said temperature produces thermally induced deformation of said substrate, said temperature being measured by said at least one temperature sensor embedded in said substrate table, said projection system controller being arranged to adjust said patterned radiation beam properties to compensate for the thermally induced deformation of the substrate thus calculated. 57. A device manufacturing method, comprising: Provide a lighting system that modulates the radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table supporting the substrate; providing a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; providing a liquid supply system for at least partially filling a gap between a final element of said projection system and said substrate with liquid; providing a sealing member substantially containing said liquid in a gap between said final element of a projection system and said substrate; and A net rate of evaporation of liquid provided by the liquid supply system is controlled. 58. A method of manufacturing a device, comprising: Provide a lighting system that modulates the radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table supporting the substrate; providing a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; providing a liquid supply system for at least partially filling a gap between a final element of said projection system and said substrate with liquid; providing a sealing member substantially containing said liquid in a gap between said final element of a projection system and said substrate; and providing a substrate table displacement system that moves the substrate table along a predetermined path relative to the sealing member, thereby moving the target portion on the surface of the substrate; and At least a portion of the substrate is heated according to at least one of position, velocity, acceleration, and predetermined path of the substrate table relative to the sealing member, a local substrate temperature, and a local substrate table temperature. 59. A device manufacturing method, comprising: Provide a lighting system that modulates the radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table supporting the substrate; providing a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; providing a liquid supply system for at least partially filling a gap between a final element of said projection system and said substrate with liquid; providing a sealing member substantially containing said liquid in a gap between said final element of a projection system and said substrate; providing a gas seal that controls the amount of liquid escaping from said sealing member through a gap defined on one side by a boundary of said sealing member on one side and on a second side by said substrate; providing a gas seal comprising a gas inlet through which gas is supplied to the region within said gap, and a vacuum exhaust outlet through which gas supplied by said gas inlet is removed from the region within said gap, said gas inlet and a vacuum exhaust outlet are respectively connected to a gas inlet pipe and a vacuum exhaust outlet pipe embedded in the sealing member. The temperature of the sealing member is stabilized. 60. A method of manufacturing a device, comprising: Provide a lighting system that modulates the radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table supporting the substrate; providing a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; providing a liquid supply system for at least partially filling a gap between a final element of said projection system and said substrate with liquid; providing a sealing member substantially containing said liquid in a gap between said final element of a projection system and said substrate; providing a channel network embedded in said substrate table, and The temperature and flow rate of a heat exchange fluid flowing through the channel network is controlled. 61. A method of manufacturing a device, comprising: Provide a lighting system that modulates the radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table supporting the substrate; providing a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; wherein The substrate table includes at least one integrated local temperature control system comprising: A temperature sensor coupled to a heater arranged to generate heat when the local temperature measured by the temperature sensor is below a predetermined reference value and to cease generating heat when the local temperature exceeds the predetermined reference value. 62. A method of manufacturing a device, comprising: Provide a lighting system that modulates the radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table supporting the substrate; providing a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; providing at least one temperature sensor for measuring the temperature of at least a portion of at least one of the substrate, the substrate table, and the substrate holder; and A property of the patterned radiation beam is adjusted based on the temperature measured by the at least one temperature sensor. 63. A method of manufacturing a device, comprising: Provide a lighting system that modulates the radiation beam; providing a support for supporting a patterning device capable of imparting a pattern in its cross-section to the radiation beam to form a patterned radiation beam; providing a substrate table supporting the substrate; providing a projection system for projecting a patterned beam of radiation onto a target portion of a substrate; providing a liquid supply system for at least partially filling a gap between a final element of said projection system and said substrate with liquid; providing a sealing member substantially containing said liquid in a gap between said final element of a projection system and said substrate; and providing a substrate table displacement system that moves the substrate table along a predetermined path relative to the sealing member, thereby moving the target portion on the surface of the substrate; and A microwave source and a microwave container device are used to heat the liquid on the surface of the substrate.

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